The present embodiments relate to an interconnect for a block detector of a positron emission tomography (PET) system.
Photomultiplier tubes (PMTs) are used in block detectors of PET systems. The PMTs detect light generated by scintillation crystals. For example, four PMTs detect light generated by an array of crystals. Four signals are generated. The signals from the PMTs are communicated over a cable, such as category 5 (CAT5) cable, to a detector circuit for signal processing, event discrimination, and time stamping. Due to the different amounts of twist for different pairs of wires in CAT5 cable, timing performance of the PET system may be degraded.
The PMTs may not be balanced or uniform, resulting in different signal levels for a same amount of light. Aging of the PMTs may cause changes in the relative signal levels. To better equalize the signal levels, the PMTs are gain adjusted. Analog potentiometers (POTs) adjust the gain of the PMTs in an initial calibration. A variable gain amplifier in the detector circuit may account for signal changes due to aging. However, more effective gain control is desired.
In single photon emission computed tomography (SPECT), the gain for PMTs may be implemented by a bias change of dynodes. The gain is controlled digitally. Printed circuit board, ribbon cable, and flexible circuit interconnect are used for transmitting the digital gain control. However, ribbon cabling may have interference problems and result in difficulty in maintenance.